Trimming mechanism for sewing machines



ot. 5 192s. l11,602,144,

S. W. AVIS i TRIMMING MECHANISM FOR SEWING MACHINES Original Filed Julyl, 1920 4 Sheets-Sheet 2 Oct. ,5 1926. s. w. Avls ATRIMMING MECHANISMFOR SEWING MACHINES Original Filed July l). 1920 4 Sheets-Sheet zve foroct. 5 1926. 1,602,144

S. W. AVIS TRMMING MECHANISM Fon SEWING ,MACHINES original Filed July 1,1920 '4 sruaets-sr1ee'c'4,

Patented @et 5, i926.

nenti.. i states. Leaieniifessics.f

y maant.

Vsniiun'i'in w. Avis, or WEST iii'lri'ritcnn, ccnivlacmronr.

Tananarive' i/,inonfivnisar "non snwiivei'iuacninns.

eifiginai appiieation flied July 1, 192e, serial no. 393,223.-Y Dividedand thisQappiiqt-.toa inea Auguste,

' .l Renewed 12,"l22g` y .1

. y1921, Serial No. 489,353.

This invention relates particularly" to the ytrimming mechanismsdesigned to be *ap-y plied to those sewing machines whichvhave" needleand two loopers that stitchfwith two or three threads Y and arecommonly;

vknown as overseain machines, suchfa ma` chine being set forth iiiapplicationllo..4

f 893,223 filed by me'Jul'y 1', 1920, fromv which the subject 'of thisapplication has been divided.

The olojectA ofthe inventionis to pro` vide a suitable work trimmingmechanism ,for a machine of this class infwhich the mechanisms aresimple, cheap and durable; are easily adJusted so the machine will belcapahle'of stitching a large variety of work;V

' are lccatedso as to permit maximum freedoni in the manipulation of thework; and

are `vdesigned so they can run atvery high speeds Vwith 'a minimumexpenditure of power and without ob]ectionabl`e vibration andgproduce astitch of desired uniformity on different thicknesses offinaterial. n

rthese ob]ects are attained by designing the mechanisms whichactuate thestitch forming needle andfl'oopers,` work controlling ner that themachine Awill run at high speed and perform its work satisfactorily.

n the accompanying drawings, Figure 1 Vshows a plan of the machineprovided with a trimming mechanism constructed according to thisinvention. Eig. 2 shows aside elevation of the machine. Fig. 3 shows afront elevation of the same. Fig. l shows a planvv of the machine withthev cover plate removed and a portion of the frame broken away.' Fig. 5is a vertical section onthe plane indicated bythe dotted line -.onFigui. Fig. ,6- is a verticalV section onv the plaiieindicated by thedotted. line 6-6 on Fig. 1. Fig. 7 is avertical'section on thevrplaneindicated by the line 7-7 on Fig. 1.

i `dic/ated byV the dotted line 8 Fig. S is avertical-section onthe'pla'ne in- 8 onlig. 2. Fig. 9 is aside view of theV front feeddogand its vis a view of the mechanism.foroscillating the Afeed dogs. 11; a'face view ottliey trimmer head.

"needle plate', Fig'. 6.v

reciprocating mechanism. Fig. 11()Y InA the .machine,"illustratedg the"needle, loopeis, feed dogs and trimmer la're'allacti'iated freinasinglerotatory shaft 1 which: is supported below*r the wcrk plateg2iwithijits* axis parallel Vwith the. line `*of* feed of .thev work tobe stitched on 'the machine.l This shaft' is supported by anti-frictionbearings 3 held inra cast ironv lskeleton hed trainev 4 which isenclosed in a tight casing that is adapted'to .hold a supplyo'f'lubificantl'j Gn `the end of the shaft outside the casing is apulley 6 which may be'driveii'loyfabelt'or inotor Vas desired, Fig.` 4*.f

In the interiorof they casing'the shaft carries a driiinf? with a canigroove 8 in its-periphery. 'Lying in this'cam groove is a roll o e]projects downward within the 'casing fromy one end of the conical arbor11 that"isqitted `in a long tapering hearing :in the needle carrierAblock 12 which is* secured-to the'top kI5 .lof the bed frame, Fig. 5.Extending upwardlygfrom the other end ofthe arhorf .through 4the vblockand a Vslot iii-the work platepis a needle carrier 13 the upper end oflwhich carries Vthe curved 'needle 11i-.fi The cam oscillates vthe ineedle 4carrier *at the `'proper intervals tov swing' the needle pointdown through and return it out of the usual Opening in the needle platev16 that' isset lhush with the work plate,*Fig.'6.

11n theenvd face of thedrum`7 isacani groove 17 and lying in thisgroove-are'frollers 18 and19 on the 'ends lof short rocker arms 20 and21 which project fromthe looper carriers"22 and 23.v `rlhe loopercarriers are lheld iiibearings iiitheloo'per carrier'blo'ck 24vtha't'fis fastened tol the top of fthe bed frame,v Fight. @The yloopers25 vand 26"eX- tend radially from near one end' of the looper carriers.The needle swings down and' up through thene'e'dle openingin the needleplate in a plane parallel with'the "line of Yfeed while theloopersoscillateirr planes transverse to the line of yfeed', the -lower llooper25 oscillating below the 'needle yplate 'y and the upperV l'ooper 26swinging from'l beon .the lower end `of the lever 10 which neathv around"one sideo'ver the topfoftlie i On thel shaft 1 nea-r one' .V727lwhich'actuatesthe front toothed feed dog y28 and the rear toothed-feedVdog297This single canithrough theconnecting mecha-V nisms r.imparts kavloiigitudinal recprocatory ff movement forward and back to the feeddogs and gives them a transverse oscillatory movement so they are raisedup through the needle plat-e when forward and lowered below the needleplate when back. Therear feed dog is attached to a carri-er which has acylindrical under surface that fits ,in a correspondingly shaped cavityformed in the top of the feed dog block 3l secured Ato the top of thelo-oper carrier block, Fig.V

(i. Y Projecting downward `from the rear feed dog carrier in front ofthe feed dog block are-a pair of lugs 32 into the yopening between whichextends a toothBS projecting upward from a fork 334 that is mounted onVa stud 35, Fig. 10. rfhis fork straddles the cam 27 so that therotation ofthe cam oscillatesthe fork and causes the rearfeed dogcarrier tol-rock ron its longitudinal axis at the proper time. Y, j

The front feed dog is attached to a carrier 36 Ywhich has an angularlower surface that fits in an angular cavity in the top of the rear feeddog carrier. The upper surface ofthe front feed dog carrier has acylindrical cavity, and fitting in this and retaining the carrier in`place is a plate 37 that is fastened to the under side of thew-orkplate, Figs. 8 and l0. The under curved surface of the rear feeddog carrier and the upper curved surface of the front feed dog carrierare concentric. As a result of this construction thefront feed dogcarrier is oscillated with the rear feed dog carrier, but is free to bemoved longitudinally independently of the rear feed dog carrier.

rifhe feed dog carriers are reciprocated by meansy which are adjustableindependently of leachother so that a variable feed may be obtained andthe changes made while the machine isrunning. A section of the cam 27 isembraced by a yoke 38, that is located in an opening in the bed plate infront of the fork, in such manner that the rotation of the cam moves theyoke up and dowmFig. 8. A roller 39 mounted onthe bed frame extends intolan opening between'two arms 40 which project from the bottom of theyoke and as- Cil sists in guiding theyole. The connections between theyoke and feed dog carriers are similar but independently adjustable.AThe yoke on each side hasa roller 4lV which occupies a radial slot 42in the face of an adjustable bell crank plate 43 that has an arbor 44which is mounted eccentrically in a cylinder 45, Fig. 8. Each cylinderis rotatably located in a .hub46 projecting inward fro-m the side of thecasing. `By means of the handles 47 the cylinders maybe rotated in orderto change the angular: relations of theaXes of `the bellerank plates tothe ares of the rollers onvthe yoke which engage and oscillatethe crank.plates as the yoke moves up ganddown.l`

Lying in a curved slot 48 inl'thevface of 1,eoe,144

each crank plate is a roller 49 on an angle lever 50, Fig. 9. One .anglelever has a solid arbor 5l and the 'other a tubular arbor 52 thatsurrounds the solid arbor and is fitted in a bearing in the end of thebed frame, Fig. 8. The angle lever on one side at its upper endV has aroller 53 engaging between the walls of .an opening 54 in the side nearthe frontend of the rear feed dog carrier, Fig. 4. The angle lever onthe other side at its upper end has a roller 55 engaging between thewalls. of an opening. 56 in the side near the front end of the frontfeed dog carrier, Fig-j4.

rfhe cam imparts a vertical reciprocation to the yoke. This rocks thebell crank plates which oscillate the angle levers that reciproVA cate'the feed dogs. which support the arbors of the bell crank plates andchanging the angular relations of the axes of the plates to the aries ofthe rolle-rs carried by the yoke the reciprocatory movement of the feeddogsmay be. altered at any time without interfering Vwith the running ofthe machine. ith the mechanism described the ,amount of feed of the dogsand the relations of the movements of the dogs to eachother may bevaried independently as desired, according to the characterof the workbeing operated upon. l

The presser foot79 pivotally mounted onthe lower end of la. finger 8Owhich is hinged'to the end of an arm 8l that is pivoted to the side wallof a cover 82 on 'one side near the rear of the machine. A spring 83holds the presser foot down. rllhe tension of this spring is regulatedby a screw 84. A A.

The trimmer has a blade 57 which is normally stationary and a/co-operating blade 58 that oscillates with relation to the fixed bladefor trimming the edge of the material Vthat is being fed beneath theneedle, Figs. 7 ll. These blades are mounted in such a manner that theymay be adjusted more or less to one side` of the plane of the needle orline of stitch or swung over away from infront of the needle andloopers.

The fixed blade 57 is a curved strip which is clamped in a'cuv'rvedgroove in a housing 59 that is attached to the front end of sleeve 60.rlhis sleeve islheld in the upper part of a yoke-shaped frame Gl' whichis pivotally mounted on an arbor @secured in an upward extension v onone side near the 7i By turning the cylinders eccentric 71 keyed on thedriving shaft back of the needle and looper cam drum, Figs. 5, 7. rlherotation of the eccentric through Ythe lever, link and arm rocks the saft 65 74 coincides with the axis of the connection y between the shaftarm 67 and the link 68, Fig. 4, and the axis of the pivot of the link74- coincides with the axis of the connection between the link 68 andthe bell crank lever 69, thus the trimming blades are mounted in partssupported by a parallel link mechanism. By turning'the handle 75 thetrimming lades may be adjusted in a substantially horizontal planetoward or from the Vline of feed of cloth for varying the distancebetween the line of needle punctures and the edge to be trimmed. l'ithsuch a parallel motion adjustment the'cutting edges of the trimmerremain practically in the same horizontal plane for all desired var:-itions in width of seam and thus will leave the clothA lying on theneedle plate and ensurea uniform width of seam. By turning the handle 75way down the housing containing the trimming blades may be swung over toone side out of the way so as to permit free access to the points ofthe'needle and the loopers for threading or other purposes. In the sideof the main casing is a curved slot 77, Fig. 6, through which theoscillatory trimmer shaft may pass when the housing and frame are swungover for adjustment or for moving thecutters out of the way, and securedto the shaft 66 inside of the plate 7 6 is a curved shutter 78 whichcovers the slot 77, Fig. l. I

The invention claimed is:

l. In a sewing machine the combination with the stitching and feedingmeans, ofv a trimming mechanism comprising a fixed cutter, a movablecutter, means for actuating the movable cutter, a support for saidcutters, and a parallel link mounting for said support.

2. In a sewing machine the combination with the stitching and feedingmeans, of a trimming lmechanism comprising co-operating cutters, meansfor actuating the cutters, a support for said cutters, and a parallellink mounting for said support.

. 3. In a sewing machine the combination i with the stitching andfeeding means, of

trimming mechanism comprising, a curved fixed cutter, a curvedoscillatory cutter that co-operates therewith, mechanism for oscillatingthe latter cutter, a frame supporting said cutters, and a parallel linkmounting for saidframe 4. Iny a sewing machine the combination with thestitching and feeding means, of a trimming mechanism comprising a curvedfixed cutter, a curved oscillatory cutter that co-operates therewith, anoscillatory frame support-ing said cutters, and a parallel linkconnection for adjusting said frame.

In a sewingk machine. the combination with the stitching and feedingmeans, of a trimming mechanism comprising a housing,

a cutter lixed inV said housing, a cutter movable in saidhousmg, anoscillatory support l for said housing, and parallel link connectionsforactuating the movable cutter and adjustingfthe housing.

ln a sewing machine the combination with the stitching and feedingmeans, of a trimming mechanism comprising a housing, an oscillatorysupport for the housing, a cutter iixed in said housing, an oscillatorycutter in said housing, and coinciding parallel link connections foroscillatingy said housing and Ysaid oscillating cutter in the housing. A

7. In a sewing machine the combination with the stitching and feedingmeans, of a Atrimming mechanism.comprising a fixed cutter, anoscillatory cutter, and coinciding parallel link connections forsupporting said.

cutters and for actuating the oscillatory cutter.

8. In a sewing machine the combination with the stitching and feedingmeans, of a trimming mechanism comprising a relatively fixed curvedcutter blade, an oscillatory curved cutter blade, mechanism foroscillating the latter blade toward and from the former blade in an arcthe axis of which is parallel to the line of feed of work through themachine, and an oscillatory support for the blades, said blades beingmounted as a unit on said support, whereby they may be adjustedcoincidently toward or from the line of work feed while the machine isin op eration.

9,111 a sewing machine the' combination with the stitching and feedingmeans and a common cam shaft, of a trimming mechanism comprising arelatively fixed curved cutter blade, an oscillatory curved cutterblade, mechanism operatedv from the cam shaftfor oscillating the latterblade toward and from the former blade in an arc the axis of which isparallel to theA axis of the cam shaft, and an oscillatory supportcarrying the critter blad-es.

10. In a sewing machine the combination with the lstitching and feedingmeans, of

lili) Jformer blade in an arc the axis et which is parallel to the lineofteed et work' through the machine, an adjustable housing carrying saidblades, and means vforadjusting' said housing in a substantiallyhorizontal plane toward and from the line et feed of work through themachine.

ll. in a sewing machine the combination with the stitching and feedingmeans, or a trimming mechanism comprising a pair et curved cutterblades, mechanism 'for causing the cooperation of sait blades, and acommon oscillatory support for said blades, said blades and' mechanismbeing mounted on said support so that they may be adjusted together as aunit toward and trom the line oit feed ot work through the machine.

l2. ln a sewing machine the combination Vith the stitching and feedingmeans, or" a trimming mechanism comprising a pair et curved cutterblades, mechanism for causing the oscillation ot one ot seid blades, anda common oscillatory support Yfor said blades whereby said blades mag7be adjuster together as a unit in a substantially hori- Zontal planetoward and trom the line et feed of work through the machine.

13. In a sewing` machine having a. work plate, the combination with thestitching and feeding means, ot a trimming mechanism comprising arelatively iixed cutter supported below the work plate, an oscillatorycutter ,supported above the work plate, mechanism foro scillating thelat-ter cutter toward and from the former cutter in an arc the axis ofwhich is parallel to the line of feed of work through the machine.

14. ln a sewing machine having a work plate, the combination with thestitchingland feeding means, of a trimming mechanism comprising a pairet curved cutters one of which is mounted below the work plate and theother of which is oscillated and is mounted above the work plate,mechanism for causing the oscillation ot said upper cutter, and meansrsupporting said cutters and mechanism whereby they may be adjusted asunit toward and 'from the line oit feed 01"' work through the machine.

l5. In a sewing machine having` a worh plate, the combination with thestitching and feeding means, of a trimming mechanism comprising ahousing, means for adjusting the housing toward and from the line et*feed ci worlt through the machine, a cutter blade fixed to the housingbelow the plane of the work plate, a cutter blade held by the housingabove the plane of the work plate, and mechanism for oscillating thelatter cutter blade toward and from the former cutter blade.

SAMUEL W. AVIS.

